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routing.c
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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2007-2020 B.A.T.M.A.N. contributors:
*
* Marek Lindner, Simon Wunderlich
*/
#include "routing.h"
#include "main.h"
#include <linux/atomic.h>
#include <linux/byteorder/generic.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/jiffies.h>
#include <linux/kref.h>
#include <linux/netdevice.h>
#include <linux/printk.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <uapi/linux/batadv_packet.h>
#include "bitarray.h"
#include "bridge_loop_avoidance.h"
#include "distributed-arp-table.h"
#include "fragmentation.h"
#include "hard-interface.h"
#include "icmp_socket.h"
#include "log.h"
#include "network-coding.h"
#include "originator.h"
#include "send.h"
#include "soft-interface.h"
#include "tp_meter.h"
#include "translation-table.h"
#include "tvlv.h"
static int batadv_route_unicast_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if);
/**
* _batadv_update_route() - set the router for this originator
* @bat_priv: the bat priv with all the soft interface information
* @orig_node: orig node which is to be configured
* @recv_if: the receive interface for which this route is set
* @neigh_node: neighbor which should be the next router
*
* This function does not perform any error checks
*/
static void _batadv_update_route(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
struct batadv_hard_iface *recv_if,
struct batadv_neigh_node *neigh_node)
{
struct batadv_orig_ifinfo *orig_ifinfo;
struct batadv_neigh_node *curr_router;
orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
if (!orig_ifinfo)
return;
spin_lock_bh(&orig_node->neigh_list_lock);
/* curr_router used earlier may not be the current orig_ifinfo->router
* anymore because it was dereferenced outside of the neigh_list_lock
* protected region. After the new best neighbor has replace the current
* best neighbor the reference counter needs to decrease. Consequently,
* the code needs to ensure the curr_router variable contains a pointer
* to the replaced best neighbor.
*/
/* increase refcount of new best neighbor */
if (neigh_node)
kref_get(&neigh_node->refcount);
curr_router = rcu_replace_pointer(orig_ifinfo->router, neigh_node,
true);
spin_unlock_bh(&orig_node->neigh_list_lock);
batadv_orig_ifinfo_put(orig_ifinfo);
/* route deleted */
if (curr_router && !neigh_node) {
batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
"Deleting route towards: %pM\n", orig_node->orig);
batadv_tt_global_del_orig(bat_priv, orig_node, -1,
"Deleted route towards originator");
/* route added */
} else if (!curr_router && neigh_node) {
batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
"Adding route towards: %pM (via %pM)\n",
orig_node->orig, neigh_node->addr);
/* route changed */
} else if (neigh_node && curr_router) {
batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
"Changing route towards: %pM (now via %pM - was via %pM)\n",
orig_node->orig, neigh_node->addr,
curr_router->addr);
}
/* decrease refcount of previous best neighbor */
if (curr_router)
batadv_neigh_node_put(curr_router);
}
/**
* batadv_update_route() - set the router for this originator
* @bat_priv: the bat priv with all the soft interface information
* @orig_node: orig node which is to be configured
* @recv_if: the receive interface for which this route is set
* @neigh_node: neighbor which should be the next router
*/
void batadv_update_route(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
struct batadv_hard_iface *recv_if,
struct batadv_neigh_node *neigh_node)
{
struct batadv_neigh_node *router = NULL;
if (!orig_node)
goto out;
router = batadv_orig_router_get(orig_node, recv_if);
if (router != neigh_node)
_batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
out:
if (router)
batadv_neigh_node_put(router);
}
/**
* batadv_window_protected() - checks whether the host restarted and is in the
* protection time.
* @bat_priv: the bat priv with all the soft interface information
* @seq_num_diff: difference between the current/received sequence number and
* the last sequence number
* @seq_old_max_diff: maximum age of sequence number not considered as restart
* @last_reset: jiffies timestamp of the last reset, will be updated when reset
* is detected
* @protection_started: is set to true if the protection window was started,
* doesn't change otherwise.
*
* Return:
* false if the packet is to be accepted.
* true if the packet is to be ignored.
*/
bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
s32 seq_old_max_diff, unsigned long *last_reset,
bool *protection_started)
{
if (seq_num_diff <= -seq_old_max_diff ||
seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
if (!batadv_has_timed_out(*last_reset,
BATADV_RESET_PROTECTION_MS))
return true;
*last_reset = jiffies;
if (protection_started)
*protection_started = true;
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"old packet received, start protection\n");
}
return false;
}
/**
* batadv_check_management_packet() - Check preconditions for management packets
* @skb: incoming packet buffer
* @hard_iface: incoming hard interface
* @header_len: minimal header length of packet type
*
* Return: true when management preconditions are met, false otherwise
*/
bool batadv_check_management_packet(struct sk_buff *skb,
struct batadv_hard_iface *hard_iface,
int header_len)
{
struct ethhdr *ethhdr;
/* drop packet if it has not necessary minimum size */
if (unlikely(!pskb_may_pull(skb, header_len)))
return false;
ethhdr = eth_hdr(skb);
/* packet with broadcast indication but unicast recipient */
if (!is_broadcast_ether_addr(ethhdr->h_dest))
return false;
/* packet with invalid sender address */
if (!is_valid_ether_addr(ethhdr->h_source))
return false;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, 0) < 0)
return false;
/* keep skb linear */
if (skb_linearize(skb) < 0)
return false;
return true;
}
/**
* batadv_recv_my_icmp_packet() - receive an icmp packet locally
* @bat_priv: the bat priv with all the soft interface information
* @skb: icmp packet to process
*
* Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
* otherwise.
*/
static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
struct sk_buff *skb)
{
struct batadv_hard_iface *primary_if = NULL;
struct batadv_orig_node *orig_node = NULL;
struct batadv_icmp_header *icmph;
int res, ret = NET_RX_DROP;
icmph = (struct batadv_icmp_header *)skb->data;
switch (icmph->msg_type) {
case BATADV_ECHO_REPLY:
case BATADV_DESTINATION_UNREACHABLE:
case BATADV_TTL_EXCEEDED:
/* receive the packet */
if (skb_linearize(skb) < 0)
break;
batadv_socket_receive_packet(icmph, skb->len);
break;
case BATADV_ECHO_REQUEST:
/* answer echo request (ping) */
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto out;
/* get routing information */
orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
if (!orig_node)
goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto out;
icmph = (struct batadv_icmp_header *)skb->data;
ether_addr_copy(icmph->dst, icmph->orig);
ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
icmph->msg_type = BATADV_ECHO_REPLY;
icmph->ttl = BATADV_TTL;
res = batadv_send_skb_to_orig(skb, orig_node, NULL);
if (res == NET_XMIT_SUCCESS)
ret = NET_RX_SUCCESS;
/* skb was consumed */
skb = NULL;
break;
case BATADV_TP:
if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet)))
goto out;
batadv_tp_meter_recv(bat_priv, skb);
ret = NET_RX_SUCCESS;
/* skb was consumed */
skb = NULL;
goto out;
default:
/* drop unknown type */
goto out;
}
out:
if (primary_if)
batadv_hardif_put(primary_if);
if (orig_node)
batadv_orig_node_put(orig_node);
kfree_skb(skb);
return ret;
}
static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
struct sk_buff *skb)
{
struct batadv_hard_iface *primary_if = NULL;
struct batadv_orig_node *orig_node = NULL;
struct batadv_icmp_packet *icmp_packet;
int res, ret = NET_RX_DROP;
icmp_packet = (struct batadv_icmp_packet *)skb->data;
/* send TTL exceeded if packet is an echo request (traceroute) */
if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
icmp_packet->orig, icmp_packet->dst);
goto out;
}
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto out;
/* get routing information */
orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
if (!orig_node)
goto out;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto out;
icmp_packet = (struct batadv_icmp_packet *)skb->data;
ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
icmp_packet->ttl = BATADV_TTL;
res = batadv_send_skb_to_orig(skb, orig_node, NULL);
if (res == NET_RX_SUCCESS)
ret = NET_XMIT_SUCCESS;
/* skb was consumed */
skb = NULL;
out:
if (primary_if)
batadv_hardif_put(primary_if);
if (orig_node)
batadv_orig_node_put(orig_node);
kfree_skb(skb);
return ret;
}
/**
* batadv_recv_icmp_packet() - Process incoming icmp packet
* @skb: incoming packet buffer
* @recv_if: incoming hard interface
*
* Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
*/
int batadv_recv_icmp_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if)
{
struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
struct batadv_icmp_header *icmph;
struct batadv_icmp_packet_rr *icmp_packet_rr;
struct ethhdr *ethhdr;
struct batadv_orig_node *orig_node = NULL;
int hdr_size = sizeof(struct batadv_icmp_header);
int res, ret = NET_RX_DROP;
/* drop packet if it has not necessary minimum size */
if (unlikely(!pskb_may_pull(skb, hdr_size)))
goto free_skb;
ethhdr = eth_hdr(skb);
/* packet with unicast indication but non-unicast recipient */
if (!is_valid_ether_addr(ethhdr->h_dest))
goto free_skb;
/* packet with broadcast/multicast sender address */
if (is_multicast_ether_addr(ethhdr->h_source))
goto free_skb;
/* not for me */
if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
goto free_skb;
icmph = (struct batadv_icmp_header *)skb->data;
/* add record route information if not full */
if ((icmph->msg_type == BATADV_ECHO_REPLY ||
icmph->msg_type == BATADV_ECHO_REQUEST) &&
skb->len >= sizeof(struct batadv_icmp_packet_rr)) {
if (skb_linearize(skb) < 0)
goto free_skb;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto free_skb;
ethhdr = eth_hdr(skb);
icmph = (struct batadv_icmp_header *)skb->data;
icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
goto free_skb;
ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
ethhdr->h_dest);
icmp_packet_rr->rr_cur++;
}
/* packet for me */
if (batadv_is_my_mac(bat_priv, icmph->dst))
return batadv_recv_my_icmp_packet(bat_priv, skb);
/* TTL exceeded */
if (icmph->ttl < 2)
return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
/* get routing information */
orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
if (!orig_node)
goto free_skb;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto put_orig_node;
icmph = (struct batadv_icmp_header *)skb->data;
/* decrement ttl */
icmph->ttl--;
/* route it */
res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
if (res == NET_XMIT_SUCCESS)
ret = NET_RX_SUCCESS;
/* skb was consumed */
skb = NULL;
put_orig_node:
if (orig_node)
batadv_orig_node_put(orig_node);
free_skb:
kfree_skb(skb);
return ret;
}
/**
* batadv_check_unicast_packet() - Check for malformed unicast packets
* @bat_priv: the bat priv with all the soft interface information
* @skb: packet to check
* @hdr_size: size of header to pull
*
* Checks for short header and bad addresses in the given packet.
*
* Return: negative value when check fails and 0 otherwise. The negative value
* depends on the reason: -ENODATA for bad header, -EBADR for broadcast
* destination or source, and -EREMOTE for non-local (other host) destination.
*/
static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size)
{
struct ethhdr *ethhdr;
/* drop packet if it has not necessary minimum size */
if (unlikely(!pskb_may_pull(skb, hdr_size)))
return -ENODATA;
ethhdr = eth_hdr(skb);
/* packet with unicast indication but non-unicast recipient */
if (!is_valid_ether_addr(ethhdr->h_dest))
return -EBADR;
/* packet with broadcast/multicast sender address */
if (is_multicast_ether_addr(ethhdr->h_source))
return -EBADR;
/* not for me */
if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
return -EREMOTE;
return 0;
}
/**
* batadv_last_bonding_get() - Get last_bonding_candidate of orig_node
* @orig_node: originator node whose last bonding candidate should be retrieved
*
* Return: last bonding candidate of router or NULL if not found
*
* The object is returned with refcounter increased by 1.
*/
static struct batadv_orig_ifinfo *
batadv_last_bonding_get(struct batadv_orig_node *orig_node)
{
struct batadv_orig_ifinfo *last_bonding_candidate;
spin_lock_bh(&orig_node->neigh_list_lock);
last_bonding_candidate = orig_node->last_bonding_candidate;
if (last_bonding_candidate)
kref_get(&last_bonding_candidate->refcount);
spin_unlock_bh(&orig_node->neigh_list_lock);
return last_bonding_candidate;
}
/**
* batadv_last_bonding_replace() - Replace last_bonding_candidate of orig_node
* @orig_node: originator node whose bonding candidates should be replaced
* @new_candidate: new bonding candidate or NULL
*/
static void
batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
struct batadv_orig_ifinfo *new_candidate)
{
struct batadv_orig_ifinfo *old_candidate;
spin_lock_bh(&orig_node->neigh_list_lock);
old_candidate = orig_node->last_bonding_candidate;
if (new_candidate)
kref_get(&new_candidate->refcount);
orig_node->last_bonding_candidate = new_candidate;
spin_unlock_bh(&orig_node->neigh_list_lock);
if (old_candidate)
batadv_orig_ifinfo_put(old_candidate);
}
/**
* batadv_find_router() - find a suitable router for this originator
* @bat_priv: the bat priv with all the soft interface information
* @orig_node: the destination node
* @recv_if: pointer to interface this packet was received on
*
* Return: the router which should be used for this orig_node on
* this interface, or NULL if not available.
*/
struct batadv_neigh_node *
batadv_find_router(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
struct batadv_hard_iface *recv_if)
{
struct batadv_algo_ops *bao = bat_priv->algo_ops;
struct batadv_neigh_node *first_candidate_router = NULL;
struct batadv_neigh_node *next_candidate_router = NULL;
struct batadv_neigh_node *router, *cand_router = NULL;
struct batadv_neigh_node *last_cand_router = NULL;
struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
struct batadv_orig_ifinfo *next_candidate = NULL;
struct batadv_orig_ifinfo *last_candidate;
bool last_candidate_found = false;
if (!orig_node)
return NULL;
router = batadv_orig_router_get(orig_node, recv_if);
if (!router)
return router;
/* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
* and if activated.
*/
if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
return router;
/* bonding: loop through the list of possible routers found
* for the various outgoing interfaces and find a candidate after
* the last chosen bonding candidate (next_candidate). If no such
* router is found, use the first candidate found (the previously
* chosen bonding candidate might have been the last one in the list).
* If this can't be found either, return the previously chosen
* router - obviously there are no other candidates.
*/
rcu_read_lock();
last_candidate = batadv_last_bonding_get(orig_node);
if (last_candidate)
last_cand_router = rcu_dereference(last_candidate->router);
hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
/* acquire some structures and references ... */
if (!kref_get_unless_zero(&cand->refcount))
continue;
cand_router = rcu_dereference(cand->router);
if (!cand_router)
goto next;
if (!kref_get_unless_zero(&cand_router->refcount)) {
cand_router = NULL;
goto next;
}
/* alternative candidate should be good enough to be
* considered
*/
if (!bao->neigh.is_similar_or_better(cand_router,
cand->if_outgoing, router,
recv_if))
goto next;
/* don't use the same router twice */
if (last_cand_router == cand_router)
goto next;
/* mark the first possible candidate */
if (!first_candidate) {
kref_get(&cand_router->refcount);
kref_get(&cand->refcount);
first_candidate = cand;
first_candidate_router = cand_router;
}
/* check if the loop has already passed the previously selected
* candidate ... this function should select the next candidate
* AFTER the previously used bonding candidate.
*/
if (!last_candidate || last_candidate_found) {
next_candidate = cand;
next_candidate_router = cand_router;
break;
}
if (last_candidate == cand)
last_candidate_found = true;
next:
/* free references */
if (cand_router) {
batadv_neigh_node_put(cand_router);
cand_router = NULL;
}
batadv_orig_ifinfo_put(cand);
}
rcu_read_unlock();
/* After finding candidates, handle the three cases:
* 1) there is a next candidate, use that
* 2) there is no next candidate, use the first of the list
* 3) there is no candidate at all, return the default router
*/
if (next_candidate) {
batadv_neigh_node_put(router);
kref_get(&next_candidate_router->refcount);
router = next_candidate_router;
batadv_last_bonding_replace(orig_node, next_candidate);
} else if (first_candidate) {
batadv_neigh_node_put(router);
kref_get(&first_candidate_router->refcount);
router = first_candidate_router;
batadv_last_bonding_replace(orig_node, first_candidate);
} else {
batadv_last_bonding_replace(orig_node, NULL);
}
/* cleanup of candidates */
if (first_candidate) {
batadv_neigh_node_put(first_candidate_router);
batadv_orig_ifinfo_put(first_candidate);
}
if (next_candidate) {
batadv_neigh_node_put(next_candidate_router);
batadv_orig_ifinfo_put(next_candidate);
}
if (last_candidate)
batadv_orig_ifinfo_put(last_candidate);
return router;
}
static int batadv_route_unicast_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if)
{
struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
struct batadv_orig_node *orig_node = NULL;
struct batadv_unicast_packet *unicast_packet;
struct ethhdr *ethhdr = eth_hdr(skb);
int res, hdr_len, ret = NET_RX_DROP;
unsigned int len;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
/* TTL exceeded */
if (unicast_packet->ttl < 2) {
pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
ethhdr->h_source, unicast_packet->dest);
goto free_skb;
}
/* get routing information */
orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
if (!orig_node)
goto free_skb;
/* create a copy of the skb, if needed, to modify it. */
if (skb_cow(skb, ETH_HLEN) < 0)
goto put_orig_node;
/* decrement ttl */
unicast_packet = (struct batadv_unicast_packet *)skb->data;
unicast_packet->ttl--;
switch (unicast_packet->packet_type) {
case BATADV_UNICAST_4ADDR:
hdr_len = sizeof(struct batadv_unicast_4addr_packet);
break;
case BATADV_UNICAST:
hdr_len = sizeof(struct batadv_unicast_packet);
break;
default:
/* other packet types not supported - yet */
hdr_len = -1;
break;
}
if (hdr_len > 0)
batadv_skb_set_priority(skb, hdr_len);
len = skb->len;
res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
/* translate transmit result into receive result */
if (res == NET_XMIT_SUCCESS) {
ret = NET_RX_SUCCESS;
/* skb was transmitted and consumed */
batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
len + ETH_HLEN);
}
/* skb was consumed */
skb = NULL;
put_orig_node:
batadv_orig_node_put(orig_node);
free_skb:
kfree_skb(skb);
return ret;
}
/**
* batadv_reroute_unicast_packet() - update the unicast header for re-routing
* @bat_priv: the bat priv with all the soft interface information
* @skb: unicast packet to process
* @unicast_packet: the unicast header to be updated
* @dst_addr: the payload destination
* @vid: VLAN identifier
*
* Search the translation table for dst_addr and update the unicast header with
* the new corresponding information (originator address where the destination
* client currently is and its known TTVN)
*
* Return: true if the packet header has been updated, false otherwise
*/
static bool
batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
struct batadv_unicast_packet *unicast_packet,
u8 *dst_addr, unsigned short vid)
{
struct batadv_orig_node *orig_node = NULL;
struct batadv_hard_iface *primary_if = NULL;
bool ret = false;
u8 *orig_addr, orig_ttvn;
if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto out;
orig_addr = primary_if->net_dev->dev_addr;
orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
} else {
orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
vid);
if (!orig_node)
goto out;
if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
goto out;
orig_addr = orig_node->orig;
orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
}
/* update the packet header */
skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
ether_addr_copy(unicast_packet->dest, orig_addr);
unicast_packet->ttvn = orig_ttvn;
skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
ret = true;
out:
if (primary_if)
batadv_hardif_put(primary_if);
if (orig_node)
batadv_orig_node_put(orig_node);
return ret;
}
static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_len)
{
struct batadv_unicast_packet *unicast_packet;
struct batadv_hard_iface *primary_if;
struct batadv_orig_node *orig_node;
u8 curr_ttvn, old_ttvn;
struct ethhdr *ethhdr;
unsigned short vid;
int is_old_ttvn;
/* check if there is enough data before accessing it */
if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
return false;
/* create a copy of the skb (in case of for re-routing) to modify it. */
if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
return false;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
vid = batadv_get_vid(skb, hdr_len);
ethhdr = (struct ethhdr *)(skb->data + hdr_len);
/* check if the destination client was served by this node and it is now
* roaming. In this case, it means that the node has got a ROAM_ADV
* message and that it knows the new destination in the mesh to re-route
* the packet to
*/
if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
ethhdr->h_dest, vid))
batadv_dbg_ratelimited(BATADV_DBG_TT,
bat_priv,
"Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
unicast_packet->dest,
ethhdr->h_dest);
/* at this point the mesh destination should have been
* substituted with the originator address found in the global
* table. If not, let the packet go untouched anyway because
* there is nothing the node can do
*/
return true;
}
/* retrieve the TTVN known by this node for the packet destination. This
* value is used later to check if the node which sent (or re-routed
* last time) the packet had an updated information or not
*/
curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
orig_node = batadv_orig_hash_find(bat_priv,
unicast_packet->dest);
/* if it is not possible to find the orig_node representing the
* destination, the packet can immediately be dropped as it will
* not be possible to deliver it
*/
if (!orig_node)
return false;
curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
batadv_orig_node_put(orig_node);
}
/* check if the TTVN contained in the packet is fresher than what the
* node knows
*/
is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
if (!is_old_ttvn)
return true;
old_ttvn = unicast_packet->ttvn;
/* the packet was forged based on outdated network information. Its
* destination can possibly be updated and forwarded towards the new
* target host
*/
if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
ethhdr->h_dest, vid)) {
batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
"Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
unicast_packet->dest, ethhdr->h_dest,
old_ttvn, curr_ttvn);
return true;
}
/* the packet has not been re-routed: either the destination is
* currently served by this node or there is no destination at all and
* it is possible to drop the packet
*/
if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
return false;
/* update the header in order to let the packet be delivered to this
* node's soft interface
*/
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
return false;
/* update the packet header */
skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
unicast_packet->ttvn = curr_ttvn;
skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
batadv_hardif_put(primary_if);
return true;
}
/**
* batadv_recv_unhandled_unicast_packet() - receive and process packets which
* are in the unicast number space but not yet known to the implementation
* @skb: unicast tvlv packet to process
* @recv_if: pointer to interface this packet was received on
*
* Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
* otherwise.
*/
int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if)
{
struct batadv_unicast_packet *unicast_packet;
struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
int check, hdr_size = sizeof(*unicast_packet);
check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
if (check < 0)
goto free_skb;
/* we don't know about this type, drop it. */
unicast_packet = (struct batadv_unicast_packet *)skb->data;
if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
goto free_skb;
return batadv_route_unicast_packet(skb, recv_if);
free_skb:
kfree_skb(skb);
return NET_RX_DROP;
}
/**
* batadv_recv_unicast_packet() - Process incoming unicast packet
* @skb: incoming packet buffer
* @recv_if: incoming hard interface
*
* Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
*/
int batadv_recv_unicast_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if)
{
struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
struct batadv_unicast_packet *unicast_packet;
struct batadv_unicast_4addr_packet *unicast_4addr_packet;
u8 *orig_addr, *orig_addr_gw;
struct batadv_orig_node *orig_node = NULL, *orig_node_gw = NULL;
int check, hdr_size = sizeof(*unicast_packet);
enum batadv_subtype subtype;
int ret = NET_RX_DROP;
bool is4addr, is_gw;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
/* the caller function should have already pulled 2 bytes */
if (is4addr)
hdr_size = sizeof(*unicast_4addr_packet);
/* function returns -EREMOTE for promiscuous packets */
check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
/* Even though the packet is not for us, we might save it to use for
* decoding a later received coded packet
*/
if (check == -EREMOTE)
batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
if (check < 0)
goto free_skb;
if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
goto free_skb;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
/* packet for me */
if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
/* If this is a unicast packet from another backgone gw,
* drop it.
*/
orig_addr_gw = eth_hdr(skb)->h_source;
orig_node_gw = batadv_orig_hash_find(bat_priv, orig_addr_gw);
if (orig_node_gw) {
is_gw = batadv_bla_is_backbone_gw(skb, orig_node_gw,
hdr_size);
batadv_orig_node_put(orig_node_gw);
if (is_gw) {